Most, if not all Linux and Mac users don't use antivirus.
If you dualboot your pc, and you catch a virus on some website or whatever. Would it affect your windows partition if it's mounted on linux? I'm not talking about viruses only, but all kind of malware.
Definitely maybe is about the best answer you can get.
It is certainly possible for a virus that runs on one OS to have a payload that can infect files that will run on another OS. If it finds an entire drive full of files that will run on another OS then it may well do it's work there. Many older viruses spread by searching network drives for various executables and inject their code into them, the theory is no different.
The only thing is that the virus will not properly run until you boot into that OS so you may have a window of opportunity to clean up the infection before it fully entrenches itself in the OS. That's also assuming your virus scanner can see and catch all the various payloads the virus may have.
That's not to say all viruses are written to do this though. You may get lucky and the virus is focused on your current OS.
Either way dual-booting is not an excuse to not have good virus protection on both of the operating systems.
Just because Windows is a much larger target for malware and viruses does not mean that other OSes should not protect themselves appropriately.
Most malware does not target Linux. I suspect that among viruses that do, few are equipped with a payload to infect Windows partitions also, although if such a partition has been mounted with rw access, it would be trivial for installed malware to do so.
Apart from anti-virus software, there are few technical defenses against malware spreading to other operating systems in a dual-boot scenario. So no, it is not safe to assume your Windows partition has not been affected, but it is likely.
